The present invention relates to precipitated particles and wellbore fluids and methods relating thereto.
In the exploration and recovery of hydrocarbons from subterranean formations, a variety of wellbore operations are performed, e.g., drilling operations, cementing operations, and stimulation operations. One physical property of the wellbore fluids used in conjunction with these wellbore operations is density. For example during drilling operations, the density of a wellbore fluid must be carefully controlled so as to exert sufficient pressure to stabilize the walls of the wellbore, e.g., to prevent blowouts, while simultaneously not exerting excess pressure that can cause damage to the surrounding subterranean formation. In another example, the density of spacer fluids and cementing operations must be carefully balanced so as to minimize or prevent mixing of other wellbore fluids on either side of the spacer fluid (e.g., a drilling fluid and a cementing fluid).
Changing the density of wellbore fluids is often achieved with the use of particles (often referred to in the art as weighting agents). The characteristics of weighting agent particles (e.g., specific gravity and particle size distribution) effect not only the density of the wellbore fluid, but also other wellbore fluid properties, like sag and viscosity. The ability to tailor the properties of the weighting agent to achieve desired wellbore fluid characteristics may allow for reduced cost by minimizing the need for other additives because the tailored weighting agent can achieve the desired wellbore fluid characteristics. However, the grinding process used to produce weighting agents provides little tailorability in terms of particle characteristics.
The characteristics of the weighting agent particles (e.g., particle shape and particle size distribution) is primarily determined by the grinding procedure and the composition of the bulk mineral including any contaminants. In some instances, sieves can be used to remove at least some of the larger or smaller particle sizes from the ground material. However, this provides limited ability to tailor the average particle size and particle size distribution of the weighting agent particles. Moreover, the grind process offers no ability to tailor the shape and morphology of the weighting agent particles. Accordingly, methods that allow for the production of weighting agents with tailored characteristics and the methods that employ the resultant wellbore fluids would be of value to one in the art.